Effects of walking on medical cost: A quantitative evaluation by simulation focusing on diabetes

Recently, the prevalence of lifestyle-related disease has increased, and its associated medical costs have become considerable. Although walking is thought to prevent lifestyle-related disease, few studies have evaluated its effect on medical costs in Japanese subjects. We aimed at evaluating the effect of walking on medical costs by simulation mainly focusing on diabetes in the Japanese population.

A Markov model focusing on diabetes was constructed. As complications of diabetes, 'dialysis', 'ischemic heart disease' and 'stroke' were included. The model has four states: 'non-diabetes', 'diabetes', 'dialysis' and 'dead', and 'ischemic heart disease' and 'stroke' were included as events that occurred in each state. The effect of walking was included as changing the rate of transition and incident rates of events.

After 10 years, the numbers of subjects with diabetes were 4.3 and 7.3% lower for daily increase of 3,000 and 5,000 steps, respectively. The numbers of cases of ischemic heart disease and stroke also decreased. Lower medical costs were also seen according to the daily increase in steps. In 10 years, the total medical costs were 5.2 and 8.4% lower for 3,000 and 5,000 steps increase, respectively. The cost reduction associated with a daily increase of 3,000 steps walked was calculated as ¥0.00146 for each step.

Walking is one of the most common and accessible forms of exercises. The present results suggested that walking reduced the medical costs associated with lifestyle-related disease, which will have a large impact on health policy.